Molecular genetic studies necessitate the ability to access and manipulate the target organism?s genomic organization. Genetic transformation of C. neoformans, regardless of system (Electroporative or Biolistic), for most part requires the use of nutritional auxotrophic host strains. However, auxotrophic mutants which could be used as hosts are not always available. We have previously cloned and characterized the GPD (Glyceraldehyde-3-phosphate dehydrogenase) gene and used its constitutive promoter for heterologous expression of the resistance to hygromycin in C. neoformans. In the past year we have demonstrated a significant enhancement in the efficiency of genetic transformation by modifications at the transcriptional termination site of the hygromycin gene by introducing downstream sequences from endogenous genes such as CAP59 and GAL7. This year we have isolated L41 gene from a cycloheximide resistant serotype D strain of C. neoformans in order to develop a selectible transformation marker expressed as resistance to cycloheximide. - Molecular tools for cryptococcal study